Fire extinguishing composition



FEE EXTINGUISHIN G COMPOSITION Paul De Bona, Paris, France, assignor to Biro Fils, Saint- Denis, France, a company of France No Drawing. Filed Apr. 16, 1958, Ser. No. 728,786

3 Claims. (Cl. 252-7) The present invention relates to an extinguisher prod uct which is particularly capable of extinguishing magnesium fires.

It is in fact known that these latter are extremely difiicult to control, particularly because of the very high temperature of the flames, this causing the dissociation of a large number of chemical products, especially water, with production of gases or of dangerous or explosive products.

The only means which has so far been suggested for extinguishing these fires consists of an oil spray; in actual fact, however, this oil does not permit the temperature of the burning mass to be lowered sufliciently and the result is in effect to add oil combustion to the combustion of the magnesium. The product according to the invention consists of a mixture of:

At least one heavy hydrocarbon.

At least one resin of the polyhydrocarbon family, and

Urea or melamine or one of their non-oxidized derivatives.

By heavy hydrocarbons, the invention covers more especially petroleum pitch and coal tar.

Among the resins which can be used, polyethylene is particularly suitable.

According to the invention, the mixture can be used in a powdered form. The above products are crushed while dry so as to pass through a number 60 screen with a retention not exceeding approximately 10%. After being dry-crushed and screened, the products are mixed and preferably coated with a water-repelling agent.

The proportions of the constituents can vary within wide limits. According to the invention, it is preferred to keep within the following limits:

rates Patent Percent Pitch or the equivalent V 5 to 20 Polyethylene or the equivalent 10 to 30 Urea or the equivalent to 80 One mixture which is very suitable is given below as a preferred but non-limitative example:

Percent Petroleum pitch 10 Polyethylene 20 Urea 70 What I claim is:

1. A composition for extinguishing fires comprising a mixture of 5-20% of a heavy hydrocarbon selected from the group consisting of petroleum pitch and coal tar, between 10-30% of resinous polyethylene, and between 5080% of a substance selected from the group consisting of urea and melamine.

2. A composition for extinguishing fires comprising a dry powdery mixture of 520% of a heavy hydrocarbon selected from the group consisting of petroleum pitch and coal tar, between 10-30% of resinous polyethylene, and between 50-80% of a substance selected from the group consisting of urea and melamine, said powder having a sufficiently small size to pass through a number screen with a retention not exceeding approximately 10%.

3. A composition for extinguishing fires comprising a mixture of 10% petroleum pitch, 20% resinous polyethylene and urea.

References Cited in the file of this patent UNITED STATES PATENTS 2,385,500 Fasold et al. Sept. 25, 1945 2,396,575 Kauth Mar. 12, 1946 2,658,877 Dreisbach et a1. Nov. 10, 1953 FOREIGN PATENTS 485,400 Germany Oct. 31, 1929 OTHER REFERENCES Knight: Preventing and Extinguishing Magnesium Fires, Metals and Alloys, May, 1943, pp. 960-966.

Brown et a1.: Methods of Extinguishing Magnesium Fires and Incendiary Bombs Composed Mainly of Magnesium, circular letter of US. Dept. of Interior, Bur. of Mines, March 23, 1942, 7 pages. 

1. A COMPOSITION FOR EXTINGUISHING FIRES COMPRISING A MIXTURE OF 5-20% OF A HEAVY HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF PETROLEUM PITCH AND COAL TAR, BETWEEN 10-30% OF RESINOUS POLYETHYLENE, AND BETWEEN 50 80% OF A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF UREA AND MELAMINE. 